1. Field of the Invention
This invention relates generally to rolling mills for rolling long products, e.g., rods, bars and the like, and is concerned in particular with an improvement to the so-called “cantilevered” roll stands, where the work rolls are mounted on the distal ends of support shafts.
2. Description of the Prior Art
Cantilevered work rolls are conventionally mounted on the distal ends of parallel support shafts. The shafts are journalled for rotation in axially spaced work and drive side bearings contained in eccentric sleeves, the latter in turn being mounted for rotatable adjustment in a cartridge housing. The roll shafts carry gears arranged to mesh with gears of the mill drive, and by simultaneously rotating the eccentric sleeves in opposite directions, symmetrical adjustments are imparted to the work rolls with respect to the mill pass line.
A more detailed description of this conventional arrangement can be had by reference to U.S. Pat. No. Re 28,107, the disclosure of which is herein incorporated by reference.
With the advent of smaller diameter work rolls, roll shaft diameters are also of necessity decreased, resulting in shaft lengths being excessively long in comparison to their diameters. Although the conventional two bearing arrangement can satisfy strength requirements reasonable well, the same is not true for stiffness, and shaft deflection becomes a problem.
One attempt at solving this problem is disclosed in U.S. Pat. No. 6,561,003 (Grimmel). Here, pressure sleeves are employed between the conventional work and drive side bearings. The pressure sleeves are hydrostatically loaded and controlled remotely to preload the shafts and thereby counteract their tendency to deflect under load. In addition to being unduly complex and expensive, this arrangement suffers from a lack of rigidity in that the roll shafts are merely contained by the pressure sleeves, with the latter lacking critical radial support from the surrounding cartridge housing.